Submission #301937

#	Time	Username	Problem	Language	Result	Execution time	Memory
301937		VEGAnn	Carnival Tickets (IOI20_tickets)	C++14	27 / 100	810 ms	79228 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>
#define PB push_back
#define sz(x) ((int)x.size())
#define all(x) x.begin(),x.end()
#define i2 array<int,2>
using namespace std;
typedef long long ll;
const int N = 1600;
const ll OO = 1e18;
ll f[N][N];
int pre[N][N];

long long find_maximum(int k, vector<vector<int>> x) {
	int n = x.size();
	int m = x[0].size();

	assert(k == 1);

	vector<vector<int>> answer;

	for (int i = 0; i < n; i++) {
		std::vector<int> row(m);

		fill(all(row), -1);

		answer.push_back(row);
	}

    for (int i = 0; i < n; i++)
    for (int j = 0; j <= n; j++)
        f[i][j] = -OO;

    f[0][0] = x[0][m - 1];
    f[0][1] = -x[0][0];

    int n2 = (n >> 1);

    for (int i = 0; i < n - 1; i++)
    for (int cnt = 0; cnt <= n2; cnt++){
        if (f[i][cnt] == -OO) continue;

        if (cnt + 1 <= n2 && f[i][cnt] - x[i + 1][0] > f[i + 1][cnt + 1]){
            f[i + 1][cnt + 1] = f[i][cnt] - x[i + 1][0];
            pre[i + 1][cnt + 1] = cnt;
        }

        if (f[i][cnt] + x[i + 1][m - 1] > f[i + 1][cnt]){
            f[i + 1][cnt] = f[i][cnt] + x[i + 1][m - 1];
            pre[i + 1][cnt] = cnt;
        }
    }

    ll ans = f[n - 1][n2];

    int i = n - 1, j = n2;

    while (i > 0){
        int pr = pre[i][j];

        if (j == pr){
            answer[i][m - 1] = 0;
        } else {
            answer[i][0] = 0;
        }

        j = pr;
        i--;
    }

    if (j == 1){
        answer[0][0] = 0;
    } else {
        answer[0][m - 1] = 0;
    }

    allocate_tickets(answer);

	return ans;
}

• Subtask 1: 11 / 11
• Subtask 2: 16 / 16
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23
• Subtask 7: 0 / 10